security/smack/smack.h

   1 /*
   2  * Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
   3  *
   4  *      This program is free software; you can redistribute it and/or modify
   5  *      it under the terms of the GNU General Public License as published by
   6  *      the Free Software Foundation, version 2.
   7  *
   8  * Author:
   9  *      Casey Schaufler <casey@schaufler-ca.com>
  10  *
  11  */
  12
  13 #ifndef _SECURITY_SMACK_H
  14 #define _SECURITY_SMACK_H
  15
  16 #include <linux/capability.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/lsm_hooks.h>
  19 #include <linux/in.h>
  20 #if IS_ENABLED(CONFIG_IPV6)
  21 #include <linux/in6.h>
  22 #endif /* CONFIG_IPV6 */
  23 #include <net/netlabel.h>
  24 #include <linux/list.h>
  25 #include <linux/rculist.h>
  26 #include <linux/lsm_audit.h>
  27
  28 /*
  29  * Use IPv6 port labeling if IPv6 is enabled and secmarks
  30  * are not being used.
  31  */
  32 #if IS_ENABLED(CONFIG_IPV6) && !defined(CONFIG_SECURITY_SMACK_NETFILTER)
  33 #define SMACK_IPV6_PORT_LABELING 1
  34 #endif
  35
  36 #if IS_ENABLED(CONFIG_IPV6) && defined(CONFIG_SECURITY_SMACK_NETFILTER)
  37 #define SMACK_IPV6_SECMARK_LABELING 1
  38 #endif
  39
  40 /*
  41  * Smack labels were limited to 23 characters for a long time.
  42  */
  43 #define SMK_LABELLEN    24
  44 #define SMK_LONGLABEL   256
  45
  46 /*
  47  * This is the repository for labels seen so that it is
  48  * not necessary to keep allocating tiny chuncks of memory
  49  * and so that they can be shared.
  50  *
  51  * Labels are never modified in place. Anytime a label
  52  * is imported (e.g. xattrset on a file) the list is checked
  53  * for it and it is added if it doesn't exist. The address
  54  * is passed out in either case. Entries are added, but
  55  * never deleted.
  56  *
  57  * Since labels are hanging around anyway it doesn't
  58  * hurt to maintain a secid for those awkward situations
  59  * where kernel components that ought to use LSM independent
  60  * interfaces don't. The secid should go away when all of
  61  * these components have been repaired.
  62  *
  63  * The cipso value associated with the label gets stored here, too.
  64  *
  65  * Keep the access rules for this subject label here so that
  66  * the entire set of rules does not need to be examined every
  67  * time.
  68  */
  69 struct smack_known {
  70         struct list_head                list;
  71         struct hlist_node               smk_hashed;
  72         char                            *smk_known;
  73         u32                             smk_secid;
  74         struct netlbl_lsm_secattr       smk_netlabel;   /* on wire labels */
  75         struct list_head                smk_rules;      /* access rules */
  76         struct mutex                    smk_rules_lock; /* lock for rules */
  77 };
  78
  79 /*
  80  * Maximum number of bytes for the levels in a CIPSO IP option.
  81  * Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
  82  * bigger than can be used, and 24 is the next lower multiple
  83  * of 8, and there are too many issues if there isn't space set
  84  * aside for the terminating null byte.
  85  */
  86 #define SMK_CIPSOLEN    24
  87
  88 struct superblock_smack {
  89         struct smack_known      *smk_root;
  90         struct smack_known      *smk_floor;
  91         struct smack_known      *smk_hat;
  92         struct smack_known      *smk_default;
  93         int                     smk_initialized;
  94 };
  95
  96 struct socket_smack {
  97         struct smack_known      *smk_out;       /* outbound label */
  98         struct smack_known      *smk_in;        /* inbound label */
  99         struct smack_known      *smk_packet;    /* TCP peer label */
 100 };
 101
 102 /*
 103  * Inode smack data
 104  */
 105 struct inode_smack {
 106         struct smack_known      *smk_inode;     /* label of the fso */
 107         struct smack_known      *smk_task;      /* label of the task */
 108         struct smack_known      *smk_mmap;      /* label of the mmap domain */
 109         struct mutex            smk_lock;       /* initialization lock */
 110         int                     smk_flags;      /* smack inode flags */
 111 };
 112
 113 struct task_smack {
 114         struct smack_known      *smk_task;      /* label for access control */
 115         struct smack_known      *smk_forked;    /* label when forked */
 116         struct list_head        smk_rules;      /* per task access rules */
 117         struct mutex            smk_rules_lock; /* lock for the rules */
 118 };
 119
 120 #define SMK_INODE_INSTANT       0x01    /* inode is instantiated */
 121 #define SMK_INODE_TRANSMUTE     0x02    /* directory is transmuting */
 122 #define SMK_INODE_CHANGED       0x04    /* smack was transmuted */
 123 #define SMK_INODE_IMPURE        0x08    /* involved in an impure transaction */
 124
 125 /*
 126  * A label access rule.
 127  */
 128 struct smack_rule {
 129         struct list_head        list;
 130         struct smack_known      *smk_subject;
 131         struct smack_known      *smk_object;
 132         int                     smk_access;
 133 };
 134
 135 /*
 136  * An entry in the table identifying IPv4 hosts.
 137  */
 138 struct smk_net4addr {
 139         struct list_head        list;
 140         struct in_addr          smk_host;       /* network address */
 141         struct in_addr          smk_mask;       /* network mask */
 142         int                     smk_masks;      /* mask size */
 143         struct smack_known      *smk_label;     /* label */
 144 };
 145
 146 #if IS_ENABLED(CONFIG_IPV6)
 147 /*
 148  * An entry in the table identifying IPv6 hosts.
 149  */
 150 struct smk_net6addr {
 151         struct list_head        list;
 152         struct in6_addr         smk_host;       /* network address */
 153         struct in6_addr         smk_mask;       /* network mask */
 154         int                     smk_masks;      /* mask size */
 155         struct smack_known      *smk_label;     /* label */
 156 };
 157 #endif /* CONFIG_IPV6 */
 158
 159 #ifdef SMACK_IPV6_PORT_LABELING
 160 /*
 161  * An entry in the table identifying ports.
 162  */
 163 struct smk_port_label {
 164         struct list_head        list;
 165         struct sock             *smk_sock;      /* socket initialized on */
 166         unsigned short          smk_port;       /* the port number */
 167         struct smack_known      *smk_in;        /* inbound label */
 168         struct smack_known      *smk_out;       /* outgoing label */
 169 };
 170 #endif /* SMACK_IPV6_PORT_LABELING */
 171
 172 struct smack_onlycap {
 173         struct list_head        list;
 174         struct smack_known      *smk_label;
 175 };
 176
 177 /* Super block security struct flags for mount options */
 178 #define FSDEFAULT_MNT   0x01
 179 #define FSFLOOR_MNT     0x02
 180 #define FSHAT_MNT       0x04
 181 #define FSROOT_MNT      0x08
 182 #define FSTRANS_MNT     0x10
 183
 184 #define NUM_SMK_MNT_OPTS        5
 185
 186 enum {
 187         Opt_error = -1,
 188         Opt_fsdefault = 1,
 189         Opt_fsfloor = 2,
 190         Opt_fshat = 3,
 191         Opt_fsroot = 4,
 192         Opt_fstransmute = 5,
 193 };
 194
 195 /*
 196  * Mount options
 197  */
 198 #define SMK_FSDEFAULT   "smackfsdef="
 199 #define SMK_FSFLOOR     "smackfsfloor="
 200 #define SMK_FSHAT       "smackfshat="
 201 #define SMK_FSROOT      "smackfsroot="
 202 #define SMK_FSTRANS     "smackfstransmute="
 203
 204 #define SMACK_DELETE_OPTION     "-DELETE"
 205 #define SMACK_CIPSO_OPTION      "-CIPSO"
 206
 207 /*
 208  * How communications on this socket are treated.
 209  * Usually it's determined by the underlying netlabel code
 210  * but there are certain cases, including single label hosts
 211  * and potentially single label interfaces for which the
 212  * treatment can not be known in advance.
 213  *
 214  * The possibility of additional labeling schemes being
 215  * introduced in the future exists as well.
 216  */
 217 #define SMACK_UNLABELED_SOCKET  0
 218 #define SMACK_CIPSO_SOCKET      1
 219
 220 /*
 221  * CIPSO defaults.
 222  */
 223 #define SMACK_CIPSO_DOI_DEFAULT         3       /* Historical */
 224 #define SMACK_CIPSO_DOI_INVALID         -1      /* Not a DOI */
 225 #define SMACK_CIPSO_DIRECT_DEFAULT      250     /* Arbitrary */
 226 #define SMACK_CIPSO_MAPPED_DEFAULT      251     /* Also arbitrary */
 227 #define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
 228 /*
 229  * CIPSO 2.2 standard is 239, but Smack wants to use the
 230  * categories in a structured way that limits the value to
 231  * the bits in 23 bytes, hence the unusual number.
 232  */
 233 #define SMACK_CIPSO_MAXCATNUM           184     /* 23 * 8 */
 234
 235 /*
 236  * Ptrace rules
 237  */
 238 #define SMACK_PTRACE_DEFAULT    0
 239 #define SMACK_PTRACE_EXACT      1
 240 #define SMACK_PTRACE_DRACONIAN  2
 241 #define SMACK_PTRACE_MAX        SMACK_PTRACE_DRACONIAN
 242
 243 /*
 244  * Flags for untraditional access modes.
 245  * It shouldn't be necessary to avoid conflicts with definitions
 246  * in fs.h, but do so anyway.
 247  */
 248 #define MAY_TRANSMUTE   0x00001000      /* Controls directory labeling */
 249 #define MAY_LOCK        0x00002000      /* Locks should be writes, but ... */
 250 #define MAY_BRINGUP     0x00004000      /* Report use of this rule */
 251
 252 #define SMACK_BRINGUP_ALLOW             1       /* Allow bringup mode */
 253 #define SMACK_UNCONFINED_SUBJECT        2       /* Allow unconfined label */
 254 #define SMACK_UNCONFINED_OBJECT         3       /* Allow unconfined label */
 255
 256 /*
 257  * Just to make the common cases easier to deal with
 258  */
 259 #define MAY_ANYREAD     (MAY_READ | MAY_EXEC)
 260 #define MAY_READWRITE   (MAY_READ | MAY_WRITE)
 261 #define MAY_NOT         0
 262
 263 /*
 264  * Number of access types used by Smack (rwxatlb)
 265  */
 266 #define SMK_NUM_ACCESS_TYPE 7
 267
 268 /* SMACK data */
 269 struct smack_audit_data {
 270         const char *function;
 271         char *subject;
 272         char *object;
 273         char *request;
 274         int result;
 275 };
 276
 277 /*
 278  * Smack audit data; is empty if CONFIG_AUDIT not set
 279  * to save some stack
 280  */
 281 struct smk_audit_info {
 282 #ifdef CONFIG_AUDIT
 283         struct common_audit_data a;
 284         struct smack_audit_data sad;
 285 #endif
 286 };
 287
 288 /*
 289  * These functions are in smack_access.c
 290  */
 291 int smk_access_entry(char *, char *, struct list_head *);
 292 int smk_access(struct smack_known *, struct smack_known *,
 293                int, struct smk_audit_info *);
 294 int smk_tskacc(struct task_smack *, struct smack_known *,
 295                u32, struct smk_audit_info *);
 296 int smk_curacc(struct smack_known *, u32, struct smk_audit_info *);
 297 struct smack_known *smack_from_secid(const u32);
 298 char *smk_parse_smack(const char *string, int len);
 299 int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
 300 struct smack_known *smk_import_entry(const char *, int);
 301 void smk_insert_entry(struct smack_known *skp);
 302 struct smack_known *smk_find_entry(const char *);
 303 int smack_privileged(int cap);
 304
 305 /*
 306  * Shared data.
 307  */
 308 extern int smack_enabled;
 309 extern int smack_cipso_direct;
 310 extern int smack_cipso_mapped;
 311 extern struct smack_known *smack_net_ambient;
 312 extern struct smack_known *smack_syslog_label;
 313 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
 314 extern struct smack_known *smack_unconfined;
 315 #endif
 316 extern int smack_ptrace_rule;
 317
 318 extern struct smack_known smack_known_floor;
 319 extern struct smack_known smack_known_hat;
 320 extern struct smack_known smack_known_huh;
 321 extern struct smack_known smack_known_invalid;
 322 extern struct smack_known smack_known_star;
 323 extern struct smack_known smack_known_web;
 324
 325 extern struct mutex     smack_known_lock;
 326 extern struct list_head smack_known_list;
 327 extern struct list_head smk_net4addr_list;
 328 #if IS_ENABLED(CONFIG_IPV6)
 329 extern struct list_head smk_net6addr_list;
 330 #endif /* CONFIG_IPV6 */
 331
 332 extern struct mutex     smack_onlycap_lock;
 333 extern struct list_head smack_onlycap_list;
 334
 335 #define SMACK_HASH_SLOTS 16
 336 extern struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
 337
 338 /*
 339  * Is the directory transmuting?
 340  */
 341 static inline int smk_inode_transmutable(const struct inode *isp)
 342 {
 343         struct inode_smack *sip = isp->i_security;
 344         return (sip->smk_flags & SMK_INODE_TRANSMUTE) != 0;
 345 }
 346
 347 /*
 348  * Present a pointer to the smack label entry in an inode blob.
 349  */
 350 static inline struct smack_known *smk_of_inode(const struct inode *isp)
 351 {
 352         struct inode_smack *sip = isp->i_security;
 353         return sip->smk_inode;
 354 }
 355
 356 /*
 357  * Present a pointer to the smack label entry in an task blob.
 358  */
 359 static inline struct smack_known *smk_of_task(const struct task_smack *tsp)
 360 {
 361         return tsp->smk_task;
 362 }
 363
 364 static inline struct smack_known *smk_of_task_struct(const struct task_struct *t)
 365 {
 366         struct smack_known *skp;
 367
 368         rcu_read_lock();
 369         skp = smk_of_task(__task_cred(t)->security);
 370         rcu_read_unlock();
 371         return skp;
 372 }
 373
 374 /*
 375  * Present a pointer to the forked smack label entry in an task blob.
 376  */
 377 static inline struct smack_known *smk_of_forked(const struct task_smack *tsp)
 378 {
 379         return tsp->smk_forked;
 380 }
 381
 382 /*
 383  * Present a pointer to the smack label in the current task blob.
 384  */
 385 static inline struct smack_known *smk_of_current(void)
 386 {
 387         return smk_of_task(current_security());
 388 }
 389
 390 /*
 391  * logging functions
 392  */
 393 #define SMACK_AUDIT_DENIED 0x1
 394 #define SMACK_AUDIT_ACCEPT 0x2
 395 extern int log_policy;
 396
 397 void smack_log(char *subject_label, char *object_label,
 398                 int request,
 399                 int result, struct smk_audit_info *auditdata);
 400
 401 #ifdef CONFIG_AUDIT
 402
 403 /*
 404  * some inline functions to set up audit data
 405  * they do nothing if CONFIG_AUDIT is not set
 406  *
 407  */
 408 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 409                                char type)
 410 {
 411         memset(&a->sad, 0, sizeof(a->sad));
 412         a->a.type = type;
 413         a->a.smack_audit_data = &a->sad;
 414         a->a.smack_audit_data->function = func;
 415 }
 416
 417 static inline void smk_ad_init_net(struct smk_audit_info *a, const char *func,
 418                                    char type, struct lsm_network_audit *net)
 419 {
 420         smk_ad_init(a, func, type);
 421         memset(net, 0, sizeof(*net));
 422         a->a.u.net = net;
 423 }
 424
 425 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 426                                          struct task_struct *t)
 427 {
 428         a->a.u.tsk = t;
 429 }
 430 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 431                                                     struct dentry *d)
 432 {
 433         a->a.u.dentry = d;
 434 }
 435 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 436                                               struct inode *i)
 437 {
 438         a->a.u.inode = i;
 439 }
 440 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 441                                              struct path p)
 442 {
 443         a->a.u.path = p;
 444 }
 445 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 446                                             struct sock *sk)
 447 {
 448         a->a.u.net->sk = sk;
 449 }
 450
 451 #else /* no AUDIT */
 452
 453 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 454                                char type)
 455 {
 456 }
 457 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 458                                          struct task_struct *t)
 459 {
 460 }
 461 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 462                                                     struct dentry *d)
 463 {
 464 }
 465 static inline void smk_ad_setfield_u_fs_path_mnt(struct smk_audit_info *a,
 466                                                  struct vfsmount *m)
 467 {
 468 }
 469 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 470                                               struct inode *i)
 471 {
 472 }
 473 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 474                                              struct path p)
 475 {
 476 }
 477 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 478                                             struct sock *sk)
 479 {
 480 }
 481 #endif
 482
 483 #endif  /* _SECURITY_SMACK_H */